The present invention relates to antiperspirant compositions in the form of solid sticks. The compositions herein comprise two phases, one an anhydrous waxy phase containing antiperspirant salts and the other an alcohol gel phase which can contain deodorant materials.
Antiperspirant compositions in stick form are known in the art. Single phase antiperspirant compositions have, for example, been disclosed in Taub; U.S. Pat. No. 1,984,669; issued Dec. 18, 1934 and Procter & Gamble; British Pat. No. 1,433,695; granted Aug. 25, 1976. Stick compositions of this type typically employ large amounts of waxy materials as the vehicle which delivers the antiperspirant active to the skin. Such stick products are stable and are especially effective for delivering large amounts of antiperspirant salts to the skin.
Attempts have been made to realize deodorant and antiperspirant sticks which deliver active ingredients to the skin via a vehicle which glides easily over skin surface and which imparts a cooling sensation to the skin during and after application. Soap/alcohol gels can provide such cosmetic benefits. However, incorporation of conventional astringent antiperspirant salts into such gels tends to interfere with the gel structure and render it less cosmetically desirable. To solve such compatability problems, alcohol gel sticks have been formulated using special additives such as lactate salts. (See, for example, Teller; U.S. Pat. No. 2,732,327, issued Jan. 24, 1956 and Slater; U.S. Pat. No. 2,900,306, issued Aug. 18, 1959). Some alcohol gel antiperspirant sticks have also been formulated in two phases with an inner core containing gel-compatable antiperspirant salts and an outer shell containing deodorant materials (See Bell, U.S. Pat. No. 2,970,083, issued Jan. 31, 1961).
Combinations of a conventional waxy antiperspirant composition with a soap/alcohol gel phase to form a two phase stick composition could enhance composition efficacy and improve composition cosmetic benefits. Such combination is, however, not made without certain difficulties. While each phase alone of such a stick composition is stable, contact between the two phases can cause destructive interaction between the two phases. The alcohol gel phase experiences syneresis, a bleeding or leaking of the gelled alcohol from the gel structure or matrix. Such leaked alcohol can interact with components of the waxy phase and can thus consume or physically separate the phases, thereby resulting in an unacceptable consumer product.
Given the state of the antiperspirant stick art as described above, there is a continuing need for new and useful antiperspirant stick compositions which provide both the stability and efficacy characteristics of waxy stick compositions and the desirable application characteristics of soap/alcohol gel compositions. Accordingly, it is an object of the present invention to provide a two phase antiperspirant stick with effective antiperspirancy performance and desirable application characteristics.
It is a further object of the present invention to provide such two phase antiperspirant sticks which are dimensionally stable.
It is a further object of the present invention to provide such two phase antiperspirant sticks which are not subject to destructive interfacial interaction.
It is a further object of the present invention to provide two phase antiperspirant sticks which can deliver both antiperspirant and deodorant materials to the skin simultaneously.
It has been surprisingly discovered that the above objective can be realized and superior two phase antiperspirant sticks provided by formulating a stick comprising an anhydrous antiperspirant phase utilizing particular amounts of certain types of waxes, emollients and antiperspirant actives and a gel phase formulated with particular amounts of certain polyhydric alcohols and gel-forming agents.